[Bug] Non-system headscale user and group from DEB packages

[maxlysenko]

Is this a support request?

• This is not a support request

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

DEB packages from v0.23.0 release create non-system user and group with /home/headscale home dir and /bin/sh shell.

Expected Behavior

Creating system user and system group with /var/lib/headscale home dir and /usr/sbin/nologin shell.
Similar to the way described in thedocumentation for installation from official standalone binaries

sudo useradd \
 --create-home \
 --home-dir /var/lib/headscale/ \
 --system \
 --user-group \
 --shell /usr/sbin/nologin \
 headscale

Steps To Reproduce

Install v0.23.0 using DEB package from the GitHub releases page on a system where no headscale user and group exists.

Environment

- OS: Ubuntu 22.04
- Headscale version: 0.23.0
- Tailscale version:

Runtime environment

• Headscale is behind a (reverse) proxy
• Headscale runs in a container

Anything else?

I see that postinstall.sh was updated in #2134 after release of v0.23.0 with fixes for home dir and shell, but maybe it still makes sense to create system user and system group?
E.g. by adding -r option for useradd and groupadd and adding -S option for Alpine's addgroup, like

useradd -r -s "$HEADSCALE_SHELL" -d "$HEADSCALE_HOME_DIR" -c "headscale default user" "$HEADSCALE_USER"
groupadd -r "$HEADSCALE_GROUP"
addgroup -S "$HEADSCALE_GROUP"